Standalone-electricity-price-ticker/VERSION.md

Electricity Price Ticker – Version Information

Current firmware

• Version: 6.2.3
• Release date: 2026-04-01
• Target MCU: Seeed XIAO ESP32‑C3
• Display: 20x4 I²C LCD (PCF8574, default address 0x27)
• API endpoint: https://api.energy-charts.info/price?bzn=SI
• Resolution: 15‑minute intervals, hourly averages for overview

Highlights of v6.2.3

• BUG FIX: State-based display refresh logic
• Problem: Screen would occasionally fail to update if the ESP32 was busy (fetching data or reconnecting WiFi) during the exact 00/15/30/45 minute mark.
• Fix: Switched from "Event-Based" (refresh only AT minute X) to "State-Based" (refresh IF current time != last refresh time). This ensures the screen updates immediately even if the device was busy during the transition.

Highlights of v6.2.2

• BUG FIX: Display blank lines issue
• Problem: Sometimes rows 0 and 1 (current 15-min prices and current hour) were blank
• Cause: The "hour suppression" logic was hiding the current hour unexpectedly
• Fix:
  • Row 1 (current hour) now ALWAYS shows - suppression logic only applies to rows 2-3
  • Row 0 (15-min details) also always shows for the current hour

Highlights of v6.2.1

• BUG FIX: Fixed findCurrentPriceIndex() to return the correct current interval.
• Problem: At 17:57, it returned index for 18:00 instead of 17:45, causing display to show hour 18 instead of hour 17.
• Fix: Now calculates next 15-minute boundary and finds the last entry before that boundary.

Highlights of v6.2.0

• CRITICAL FIX: DST (Daylight Saving Time) handling is now fully fixed for all days.
• Previously, the code assumed every day has exactly 96 price entries (24h × 4). This caused incorrect price display on DST switch days:
  • Spring forward (March): Only 92 entries → wrong prices displayed
  • Fall back (October): 100 entries → wrong prices displayed
• Solution: All price lookups now use timestamp-based searching through the unix_seconds array instead of arithmetic calculation (hourIndex * 4).
• New functions: findPriceIndexForHour(), findCurrentPriceIndex(), getHourFromPriceIndex()
• Updated functions: getHourlyAverage(), display15MinuteDetails(), displayPriceRow(), displayPrimaryList(), updateLeds()
• The ticker now works correctly on all days, including DST switch days, with no manual intervention.
• Future-proof: If EU cancels DST, only the TZ_CET_CEST string needs updating (one line of code).

Previous firmware

• Version: 6.1.2
• Release date: 2026-03-11
• Target MCU: Seeed XIAO ESP32‑C3

Highlights of v6.1.2

• Fix: restore proper white LED price indicator behavior on ESP32 by avoiding mixing PWM (analogWrite) and digitalWrite on the same pin.
• Fix: LED is now truly off when backlight/LED gating turns it off (no more "dim glow").

Earlier firmware

• Version: 6.1.1 (2026-03-07) – Daily low/high marker includes negative and zero prices
• Version: 6.1.0 (2026-01-30) – Midnight fetch and market day detection fixes
• Version: 6.0.0 (2026-01-27) – NVS storage and daily fetch

For full details, see:

• CHANGELOG.md
• README.md